The actress stripped down to her bikini before getting drenched in freezing water. But before being soaked, the 41-year-old revealed that she was nominating her estranged husband to take part.

"Hi, I'm going to alsa.org to donate money for ALS, but in the meantime I'll do this and nominateChris Martin, Cameron Diaz and Stella McCartney," she told the camera, in a video posted on her Instagram.

A friend then tipped a bucket full of cold water all over the star, who shrieked and started to run away.

Gwyneth and Chris, 37, famously announced they were "consciously uncoupling" back in March but have remained on very good terms.